- Canadian Data Report of Hydrography and Ocean Sciences No. 99

Transcription

1 r i- *Uef6m r- Scientific Excellence Resource Protection & Conservation. Benefits for Canadians Excellence sdentifique. Protection el consenration des ressoums BBn6fices aux Canadiens ~ I Temperature, Salinity, and Density Data from the Hudson Strait Region During August-September, 1982 K.F. Drinkwater, G.B. Taylor and W.B. Petrie Physical and Chemical Sciences Branch Scotia-Fundy Region Department of Fisheries and Oceans Bedford Institute of Oceanography P.O. Box 1006 Dartmouth, Nova Scotia Canada B2Y 4A2 - Canadian Data Report of Hydrography and Ocean Sciences No. 99

2 Canadian Data Report of Hydrography and Ocean Sciences No, 99 TEMPERATURE, SALINITY, AND DENSITY DATA FROM THE HUDSON STRAIT REGION DURING AUGUST-SEPTEMBER, 1982 K,F. Drinkwater, G.B. Taylor and W,M. Petrie Physical and Chemical Sciences Scotia-Fundy Region Department of Fisheries and Oceans Bedford Institute of Oceanography P,O. Box 1006 Dartmouth, Nova Scotia Canada, B2Y 4A2

3 Q Minister of Supply and Services Canada 1991 Cat. No. FS 97-16/99E ISSN Correct citation for this publication: Drinkwater, K.F., G.B. Taylor and W.M. Petrie Temperature, salinity, and density data from the Hudson Strait region during August-September, Can. Data Rep. Hydrogr. Ocean Sci. 99: iv + 41 pp.

4 iii TABLE OF CONTENTS Abstract/Resume Introduction Data and Methods Graphical Presentation Acknowledgements References Figures

5 ABSTRACT Drinkwater, K.F., 6,B. Taylor and W.M. Petrie Temperature, salinity, and density data from the Hudson Strait region during August-September, $982, Can. Data Rep, Hydrogr. Ocean Sci, 99: iv + 41 pp. Measurements of temperature (T), salinity (S), and sigma-theta (a ) at 130 stations in Hudson Strait and vicinity 0 during 15 August to 7 September, 1982 are presented in graphical form. Oceanographic sections are plotted as well as contours of T and S at two depths, near surface and at 50 m. For selected stations, we also present vertical profile plots (T, S and a vs. 6 depth) and T-S diagrams (T vs. S), RESUME Drinkwater, K.F., G.B. Taylor and W,M. Petrie Temperature, salinity, and density data from the Hudson Strait region during August-September, Ocean Sci. 99: iv i- 41 pp. Can. Data Rep. Hydrogr. On presence ici des graphiques des mesures de temperature (T), de salinite (S) et de sigma-theta (a ) relevees dans stations du detroit dihudson et des environs, du 15 aogt au 17 septembre ainsi que les courbes de T et S 2i Les coupes oceanographiques y sont indiquees des profondeurs donnees, B proximite de la surface et B une profondeur de 50 m, Pour certaines stations, on presente aussi des profils verticaux (T, S et a par rapport B e rapport B S). la profondeur) et des diagrammes T-S (T par

6 Introduction This data report presents temperature, salinity, and density (sigma-8) data collected during an oceanographic cruise to Hudson Strait in August-September of Prior studies had suggested that the characteristics of the Labrador Shelf water were formed in Hudson Strait through the mixing of waters from the Baffin Island Shelf, deep waters from the Labrador Sea, and relatively low salinity waters from Hudson Bay (Dunbar 1951; Kollmeyer et al. 1967). Indeed, Kollmeyer et al. (1967) had called the region of eastern Hudson Strait the "birthplace" of the Labrador Shelf waters. Sutcliffe et al, (1983) later suggested t%lat mixing in Hudson Strait also had important biological consequences through surface nutrient enrichment and subsequent nutrient flux onto the Labrador Shelf. One of the objectives of the physical oceanographic field study in the late summer of 1982 was to improve our understanding of the circulation in Hudson Strait. A moored current meter array was deployed in the Strait immediately to the west of Ungava Bay during the cruise and was recovered during a separate voyage in October, A graphical presentation of the current meter data was provided by Drinkwater (1983) and a discussion of the mean and tidal currents from the array can be found in Drinkwater (1988)- Another major objective was to identify the primary mixing mechanism within Hudson Strait. From extensive hydrographic data collected during the cruise Drinkwater and Jones (1987) concluded that the intense mixing was of tidal origin. This was based upon a comparison of the observed density stratification with that predicted by Griffiths et al, (1981) using a numerical tidal model 3 and the h/u criteria of Simpson and Hunter (1974). With continuing interest in the oceanography of the region and the possibility of new research initiatives on the marine ecology within Hudson Strait (Percy 1990), we felt that a graphical presentation of the hydrographic data may provide useful background information for future studies.

7 Data and Methods Vertical profiles of temperature and salinity were recorded at 130 stations during a field study between 15 August and 7 September, 1982 on board the CSS Hudson. Stations were occupied off St. John's, Newfoundland (Sen, I), on the Labrador Shelf (Stn. 2-16, 89-98), in Hudson Strait (Stn , 47-79, 99-P30), in northern Hudson Bay (Stn ), in southern Foxe Basin (Stn ), and on the eastern Baffin Island Shelf (Stn ). The station positions (except station 1) are plotted in Fig. 1. temperature and salinity data were obtained at station 64 in Foxe Basin because of heavy ice cover. No The measurements were taken with a Guildline digital CTD (Conductivity-Temperature-Depth) profiler. A rosette sampler was attached to the CTD from which calibration samples were collected, typically at 10 depths per cast for salinity. Reversing thermometer temperatures were generally obtained at two depths per cast. Large spikes in the data were first removed and then calibrations were applied to the raw data file. Water densities were calculated from the corrected temperature and salinity data using the UNESCO 1980 formulation and expressed as sigma-8 (o ). The accuracy of the temperature 0 and salinity measurements are estimated at +O.OlOc and p.s,u, (practical salinity units), respectively. then smoothed and reduced to 1 data point every 2 m. The data were These smoothed data have been archived and are available from the Bedford Institute of Oceanography or the Marine Environmental Data Service (MEDS) in Ottawa. Graphic Presentations Transects of temperature, salinity, and sigma-8 are plotted in Fig. 2 through 21. Because of the relatively small changes in hydrographic properties between the closely spaced stations in the eastern entrance 6s Hudson Strait ( ; Fig. I), these data have not been plotted, Contours of temperature and salinity on depth surfaces near the surface and at 50 m are presented in Fig The final plots are vertical profiles of temperature,

8 salinity and sigma-8 plus temperature-salinity (T-S) diagrams for selected stations (Fig ). ACKNOWLEDGEMENTS We wish to thank all those who participated in the collection of the CTD data including Captain Mauger and the crew of the CSS Hudson. A special thanks to P. Jones, chief scientist of the cruise. REFERENCES Drinkwater, K,F Moored current meter data from Hudson Strait, Can. Data Rep. Fish. Aquat. Sci. No. 381, 46 PP. Drinkwater, K. F On the mean and tidal currents in Hudson Strait. Atmosphere-Ocean 26: Drinkwater, K.F, and E.P. Jones Density stratification, nutrient and chlorophyll distributions in the Hudson Strait region during the summer and their relation to tidal mixing. Cont. Shelf Res.. 7: Dunbar, M.J Eastern Arctic waters, Bull. Fish. Res. Board Can. 88, Ottawa, Ontario, 131 pp. Griffiths, D,K,, R.D. Pingree, and M, Sinclair. 1981, S tidal fronts in the near-arctic regions of Foxe Basin and Hudson Bay. Deep-Sea Res. 28: Kollmeyer, R.C., D.A. McGill and N. Corwin Oceanography of the Labrador Sea in the vicinity of Hudson Strait in 1965, U.S. Coast Guard Oceanogr. Rep. No. CG373-12, 92 pp. Percy, J Proceedings of a workshop: Marine ecosystem studies in Hudson Strait. Can. Tech. Rep. Fish. Aquat. Sci, 1770: 174 pp. Simpson, J.H. and J.R. Hunter Fronts in the Irish Ses. Nature 250:

9 Sutcliffe, W.H., Jr., R.H. Loucks, K.F. Drinkwater, and A.R. Coote Nutrient flux onto the Labrador Shelf from Hudson Strait and its biological consequences. Can. J. Fish. Aquat. Sci. 40:

10 Fig. 1. Hudson Strait and vicinity showing the location of the CTD stations.

11 Temperature u-c Kilometers Fig. 2. Transects of temperature, salinity, and density (o~) along the Labrador Shelf (Stn. 3-17).

12 55% 1 I \ " / BAFFIN ISLAND l65', HUDSON BAY c9 LABRADOR 8. SEA 9 Fig. 1. Hudson Strait and vicinity showing the location of the CTD stations.

13 Tern per Qture Kilometers Density - August 16-19,1982 Fig. 2. Transects of temperature, salinity, and density (og) along the Labrador Shelf (Stn. 3-17),

14 I Temperature 'C I Fig. 3. Transects of temperature, salinity and density (ag) in northeastern Ungava Bay (Stn, 18-20),

15 1 Temperature *C --- August 20, 1982 Kilo meters Density Fig. 4. Transects of temperature, salinity and density (08) across the mouth of Ungava Bay (Stn, 20-23).

16 20 40 Kilometers Density Fig, 5. Transects of temperature, salinity and density ( D ~ ) from Ungava Bay into Hudson Strait (Stn ).

17 Salinity I Fig. 6, Transects of temperature, salinity and densicy (ob) across Hudson Strait off Gape Hopes Advance (Stn ),

18

19 I Temperature OC August 25, 1982 Fig. 8. Transects of temperature, salinity and density (go) at the southwestern entrance to Hudson Strait (Stn ).

20 - August 25, 1982 Fig. 9, Transeces of temperature, salinity and density (ag) in northeastern Hudson Bay (Stn, 48-49).

21 0 50 ln L ti, - 0) I00 I50 2m Temperature OC I Salinity - August 26, ,.- ti, Q Density Kilometers Fig. 10. Transects of temperature, salinity and density (og) in north central Hudson Bay (Stn ).

22 - August 27, Kilometers Density Fig. 11. Transects of temperature, salinity and density (ub) in northwestern Hudson Bay (Stn, 54-56).

23 I - Kilometers Density Fig. 12, Transects of eernperature, salinity and density (ag) in northern Hudson Bay south of Southampton Island (Stn. 55, 57-58),

24 Temperature OC - August 29-31, 1982 Fig. 13. Transects of temperature, salinity and density (ag) at the southern entrance to Foxe Basin (Stn , 66).

25 , , - august 29-30, 1982 Kilometers Fig. 14. Transecrs of temperature. salinity and density (ag) in southern Foxe Basin (Stn ).

26

27 I Temperature OC I Salinity September I ' Kilometers Density Fig. 16. Transecrs of temperature, salinity and density across Hudson Strait near Charles Island (Stn ). (og)

28 - September 1-2, b4s-d-d Kilometers Fig. 17. Transects of temperature, salinity and density (ag) off soueheastern Baffin Island (Stn, 76-79).

29 Fig, 18. Transeets of temperature, salinity and density (ag) ow the southern Baffin Island Shelf (Stn ).

30 Temperature 'C \ \ Fig. 19. Transects of temperature, salinity and density on the northern Labrador Shelf (Stn ). (og)

31

32

33

34

35

36

37 SALI NI '%6 SI GMA-THETA (KG/W3) Q Z.0 ZWl SALINITY STATION 29 Fig. 26. Vertical profiles of temperature, salinity and sigma-8 and the T-S diagram at station 29 in northeastern Hudson Strait.

38 TEMPERATURE (DEG. C) SALINITY SI GMA-THETA (KG/M**~) SALINITY STATION 33 Fig. 27, Vertical profiles of temperature, salinity and and the T-S diagram at station 33 off Cape Hopes Advance.

39 TEMPERATURE (DEG. 6) SALINITY SALINITY STATION 52 Fig. 28. Vertical profiles of temperature, salinity and sigma-8 and the T-S diagram at station 52 in northern Hudson Bay.

40 TEMPERATURE (DEG. C) SALINITY lil x5.0 SIGMA-THETA (KG/M**3) i.O D SALINITY Fig, 29. Vertical profiles of temperature, salinity and and the T-S diagram at station 63 in western Foxe Basin.

41 Tl3hifPERAWm (DEG. C) SALINITY Fig, 30, Vertical profiles of temperature, salinity and sigma-8 and the T-S diagram at station 65 in eastern Foxe Basin.

42 SALINITY S I GMA-THETA (KG/ Id-3) DzLo26n2Y.028D SALINITY Fig. 31. Vertical profiles of temperature, salinity and sigma-0 and the T-S diagram at station 78 in Gabriel Strait off southeastern Baffin Island,

43 SALINITY SI GMA-THETA (KG/ W3) L n SALINITY Fig, 32. Vertical profiles of temperature, salinity and and the T-S diagram at station 83, inshore on the southern Baffin Island Shelf,

44 TEMPERATURE (DEG. C) SALINITY LO ) SI GMA-THETA (KG/M"3) SALINITY Fig. 33. Vertical profiles of temperature, salinity and sigma-b and the T-S diagram at station 88, offshore on the southern Baffin Island Shelf,

45 SALINITY SALINITY STATION 89 Fig. 34, Vertical profiles of temperature, salinity and sigma-8 and the %-S diagram at seation 89, offshore on the northern Labrador Shelf.

46 TEMPERATURE (DEG. C) -20 on SALINITY i h 2 loon Fig. 35. Vertical profiles of temperature, salinity and sigma-@ and the T-S diagram at station 96, inshore on the northern Labrador Shelf,

47 TEMIPERATURE (DEG. C) on SALINITY SALINITY STATION 180 Fig. 36, Vertical profiles of temperature, salinity and sigma-# and the T-S diagram at station 100 on the south side of the eastern entrance sf Hudson Strait.

48 TEMPERATURE (DEG. 6) SALINITY 280JUI3I.n320331] S I GMA-THETA (KG/ M"3) SALINITY Fig. 37. Vertical profiles of temperature, salinity and sigma-@ and the T-S diagram at station 105 on the north side of the eastern entrance of Hudson Strait.